Conformally-coupled dark spinor and FRW universe

TL;DR

This paper explores how conformally-coupled dark spinor fields influence the evolution of the universe within the FRW framework, providing analytic solutions and discussing their role in matter and dark energy dominance.

Contribution

It introduces a model of dark spinor fields with conformal coupling in FRW spacetime, deriving analytic solutions for the universe's expansion and exploring their cosmological implications.

Findings

Analytic solutions for the scale factor a(t) in dark spinor cosmology.

Dark spinor fields can potentially describe both matter and dark energy eras.

The energy density and pressure of dark spinors are computed in FRW spacetime.

Abstract

We study conformal coupling of dark spinor fields to gravity and calculate the energy density and the pressure of the spinor in FRW spacetime. We consider the renormalizable potential of the spinor field. In the cases where the field is proportional to some power of the cosmic scale factor $a(t)$, we determine the Hubble parameter as a function of the scale factor and find analytic solutions for $a(t)$ when the spinor field matter dilutes as the universe expands. We discuss the possibility that both matter- and dark energy-dominated eras of our universe can be described by the dark spinor.